docs: def event_type(self, event, cameo_code) -> List[str]:
          """
          Look up the event tupe of an event
          Args:
              event: one of "event1", "event2" or "event3"
              cameo_code: one of the cameo codes
  
          Returns: a list of the event types or None if the event is not relevant.
  
          """
          key = self.event_name[event]
          entry = self.mapping.get(cameo_code)
          result = None
          if entry:
              result = entry[key]
              if result is None or result == "":
                  return None
              elif not isinstance(result, list):
                  result = [result]
          return result